FACS analysis of sorted CD4⁺/Vβ5.3⁺ clonal T cells from patient C.

Approximately 10⁶ isolated malignant T cells were incubated either with (fat lines) or without (thin lines) IFN-γ (500 U/mL) for 40 hours at 37°C in a 5% CO₂ atmosphere. Then cells were washed and stained with anti-IFNγR2 antibodies (A), anti-HLA class I antibodies (B), and appropriate isotype-control antibodies for protein surface expression.